I want to connect a high-speed (20 MBytes/sec) bus to the PRU, so I’m going to do an 8-bit SPI-type interface on the PRU. The goal was to use the PRU pins on header P9 (pins 24 through 42) and write some simple PRU assembly to wait on the ‘clock’ bit, read the register, write to RAM, signal we’ve read something to PR1/the ARM, and repeat.
PR0 is going to be completely dedicated to this, and if I can get it down to a few instructions per loop, it ought to cope. What I need, though, is a way to disable the mcasp driver (I won’t be using audio). It doesn’t seem to be loaded as a separate overlay in /lib/firmware, and it doesn’t appear in /sys/devices/bone_capemgr.8/slots
I’m pretty new to this, so I’m not comfortable editing out parts of /boot/am335x-boneblack.dts that refer to mcasp unless someone tells me it’s going to be ok I’m not sure I want to reboot-to-get-the-results and then have a brick…
Any advice ?